Moving stairway



July 27, 1937,. E. M. BOUTON l 2,08`8450 MOVING STAIRWAY Filed Dec. 2o, 1954 2 sheets-sheet 1 257 75 4 j@ I 26 l INVENTOR @wwwa/Z,

BY f- AT NEY ji 52 75 t E.` M. BOUTON MOVING STAIRWAY July 27, 1937.

INVENTOR WlTNESSES:

Patented July 27, 1937 UNITED STATES MOVING STAIRWAY Edgar M. Bouton, Chicago, Ill., assignor'to Westinghouse Electric Elevator Company, Chicago, Ill., a corporation of Illinois Application December 2o, 1934, serial No. 758,4?,4y

6 Claims.

`My' invention relates to moving stairwaysin which the moving steps are operated by endless gear 'chains disposed on a plurality of sprocket wheels, and more particularly, to the control systems and safety devices for such stairways.

One object of my invention is to provide for stopping a stairway when a break occurs in its driving means.

Another object of my invention is to provide one means for stopping the driving means of the moving stairway and, after a predetermined interval, applying a second or additional means for'p'reventing movement oi' the stairway until the`-driving means is again started in a normal manner. Y

A further object of my invention isl to provide for stopping the stairway motor and the stairway, without imposing an undue strain upon the motor or upon the motor worm shaft.

It is also an object of my invention to p-rovide for so operating a stairway that it will be stopped promptly and automatically when breakage ofany part, or any dangerous condition arises in connection with the stairway.

Other objects of the invention will be apparent from the following description, takenv in conjunction withv the accompanying drawings, in which:

Figure l is a View in side elevation of the main parts of a moving` stairway embodying my invention;

Fig. 2 is a top plan view of the motive parts of the stairway shown in Fig. l; l

Fig. 3 is a view in end elevatio-n of the sprocket Wheels, and the supporting means therefor, shown at the lower landing in Figs. l and 2;

Fig. 4 is an enlarged view of the safety switch and a portion of its operating mechanism associated with the drive chain in Figs l and 2; and,

Fig. 5 is a diagrammatic representation of the electrical control system for controlling theI motor which drives the stairway.

The right-hand side of the diagram shown in Fig. 5 is drawn in what is known as the straight line style for electrical wiring, and the leithand portion provides a key to the mechanical relation between the coils and the contact members in the right-hand side of the drawings, in order that the reader may readily determine the location of any relay in the right-hand side of the diagram, the number of its contact members, and the points at which the contact members are disposed in the system.

Referring more particularly to the drawings,

I have illustrated a movingA stairway comprising an endless series of movable steps i Vdisposed to be operated along their tracks 2 by a pair of gear chains 3 and llbetween an upper landing 5 and a lower landing 6. The gear chains are supported at the upper landing by a pair of driving sprocket wheels 'l and 8 and at the lower landing. by a pair of tensioning sprocket wheels 9 and' I9. A suitable truss or frame l i of structural steel is provided for supporting the stairway betweenA its upper landin andits lower landing- The driving sprocket wheels T and 8 are positively connected by a large torque tube i3` and are mounted .by suitable rollervbearings or other means (not shown) upon a supporting shaft It, the outer ends of which are supported by a pair of suitable standards I5 and I6.

A. motor I8 is provided for driving the sprocket wheels 7 and 8 through a drivingV shaft I9,` a reduction gear 29, a driving pinion 2l, a driving chain 22 and a chain sprocket wheel 23..

which is securely attached to the driving spreek-- et wheel 'I by a plurality of bolts or rivets (not shown). c

The lower sprocket wheels 9` and I0 are connected by a sleeve or torque vtube 25 provided with suitable nangesr 26 and 2l bolted to suitable cooperating flanges 28 'and 29 `upon. the inner portions of the sprocket wheels. by a plurality of bolts 3D.. As shown, the sleeve 25.*rmly connects the sprocket wheels at the lower landing and causes them to rotate in unison with each other. ,i l

In order to keep the gear chains under such predeterminedtension as may be desirable, the sprocket wheels at the lower landing are mountedupon a pivotal carriage comprising a shaft. 3| and apair of end trucks 32 andi-B3. The shaft passes through the sleeve 25 and the axes of the gear wheels 9 and I9 and is supported at its ends by the trucks 32 and 33.Y A. set screw 34` is disposed in the upper portion of, each of between thewheels 38 andY 39 and pivotally secured to the underside of the casting v3'! in a Imounted upon the rod 55.

horizontal plane. A track rail 42 is located underneath the Wheels 38 and 39 to support the truck and a guide rail 43 is disposed on the outside of the guide wheel 40 to limit sidewise movement of the truck. 'I'he guide rail 43 may be welded to the track 42 to unite the two in a rigid angle iron track and guide.

The truck 33 is similar to the truck 32 and comprises a heavy cast frame 46, a pair of supporting wheels 48 and 49 and a guide wheel 50. A track rail 52 and a guide rail 53 are provided for the wheels 48, 49 and 59. The track rails l2 and 52 and the guide rails 43 and 53 may be suitably welded to the associated angle iron members 41 comprising a portion of the frame or truss Il.

In view of the description of the carriage for the lower sprocket wheels, it will be seen that the carriage can move back and forth on the wheels 38 and 39 and 48 and 49, and can turn in a pivotal manner by reason of the horizontally disposed guiding wheels 40 and 50.

A tensioning means 54 is provided for each truck to keep the gear chains under such tension as may be desired. Each tension device 54 comprises a rod 55 pivotally connected to the truck 32 in position to extend rearwardly through the frame member 41 and a compression spring 56 concentrically disposed on that portion of the .rod 55 extending rearwardly beyond the frame `member 41.

This spring may be held under such compres sion as is desired by means of a stop member 51 and a pair of nuts 58 also concentrically The nuts 58 are so "disposed on the screw-threaded end of the rod 55 that the position of the stop member 51 and, therefore, the amount of compression on the spring 56, may be adjusted to any desired amount by rotating the nuts. The truck 33 is provided with a tensioning means that is similar to the tensioning means described for the truck 32. Therefore, it will be obvious that the tension on the gear chains may be adjusted to any desirable amount by adjusting the nuts 58 on the rods 55.

A safety switch 6D is mounted adjacent to each of the tensioning devices 54. The switch comprises a frame 6I supported by an angle iron 62 on a portion of the truss frame Il, as shown in Figs. 1, 2 and 4. A contact member 63 is suitably mounted in the frame 6I in position to be engaged by a cooperating contact member 63a. The Contact member 63a is biased away from the contact member 63 by a compression spring 65.

A trigger 66 is provided for normally engaging a projection 64 on the spring contact member 63a and thereby hold it in engagement with the stationary contact member 63. The trigger is pivotally mounted in the frame 6| with its lower end extending downwardly into a position between a pair'of projections on the stop member 51. If the stop member 51 is moved either forwardly or backwardly beyond a predetermined distance by the operation of the tensioning devices 54, the projections will move the trigger` from the projection 64 and thereby release the contact member 63a, from the contact member 63, thus opening the switch 6U.

Hence, it will be obvious that if either of the trucks 32 or 33 moves either forwardly or backwardly beyond a predetermined distance because of the stretching or breaking of one or bothV chains or because of the steps catching on a projection, the corresponding safety switch 6l] will be opened. Also, it will be obvious that, by reason of the projection 64 on the contact member 63m, the trigger cannot again close the switch until the contact member 63a is raised by hand into engagement with the stationary Contact member. Hence a temporary movement of either of the trucks beyond a predetermined distance will cause its switch 60 to open and remain open until it is manually reset.

A motor brake 19 is mounted upon the motor shaft i9 for the purpose of stopping the motor and the stairway when desired. Any suitable brake may be employed, such as the spring-applied electromagnetically released type of brake usually associated with electric motors. When the electromagnetic coil 1I of the brake 10 is deenergized, the brake will be applied to the motor shaft to prevent rotation of the motor and the consequent operation of the driving chain 22 and the stairway steps.

The motor brake 10 is a service brake for positively stopping and holding the stairway against movement when the attendant desires to stop the operation of the stairway. The motor brake is also made responsive to the various safety devices associated with the stairway for positively stopping and holding the stairway when any dangerous condition arises except that of a break in the drive chain.

An emergency brake 13 is provided for posi-l tively stopping and holding the stairway in case of breakage of the driving chain 22. f

Any suitable emergency brake may be used, but the one illustrated is a brake of the snubber type comprising a band 14 disposed around a brake drum 15 firmly secured to the torque tube I8. The ends of the band 14 are pivotally secured to a brake lever 16 pivotally mounted in a brake support 11 securely attached to a crossmember 18 on the truss frame Il. A plurality of weights 19 are disposed on the outer end of the brake arm 15 to bias it to its brake-applyl energization of the electromagnet 8| will draw the n armature 82 upwardly and thereby pull the rod 83 and the brake lever 16 upwardly against the downward pull of the weight 19 and thus release the brake band 14 from the brake drum 15. When the electromagnet is deenergized, the upward pull upon the rod 83 ceases thereby permitting the weight 19 to exert such a downward pull on the brake lever 16 as to cause the brake band 14 to effectively apply a braking pressure to the brake drum 15 and thereby prevent any further movement of the stairway.

Normally, it would be necessary to provide for the application of the emergency brake only in the event of the breakage of the driving chain, but inasmuch as the emergency brake is held in its released condition by the electromagn'et 8!,` it will be more economical to deenergize the magnet when the stairway is not running. This will, of course, apply the emergency brake to its brake drum. Therefore, I have arranged to deenergize the emergency brake, whenever the stairway is stopped by the application of In view of this, I have pro.

within four or ve seconds after the motor brake is applied. This causes the emergency brake to become fully effective several seconds after the motor brake is made effective, and permits a saving in the current which would otherwise be necessary to maintain the emergency brake in a released condition at all times except upon breakage of the driving chain. The means for effecting the delay in the application of the emergency brake will be hereinafter de scribed.

It is, of course, advisable to apply the emergency brake instantly in the event of breakage of the driving chain because if the driving chain is broken, the brake 1| cannot then prevent movement of the stairway, even though that brake is promptly applied to prevent rotation of the motor shaft.

In order to make the application of the emer-v .gency brake responsive to breakage of the driving connections, I have provided a safety switch B6 for operation by a shoe 8l disposed to ride upon the upper surface of the driving chain. The shoe is mounted upon a rod 84 connected to the outer end of a lever 85 for operating the safety switch 85. The safety switch 86 is constructed in the same manner as the safety switch 60, shown in Fig. 4 and is so connected electrically to the electromagnetic coil 8| of the emergency brake that if the driving chain stopping of the stairway.

As another safety measure, a safety governor 90 is disposed upon one end of the motor shaft I9. The governor comprises a collar |48, a pair of governor weights |4|, and a spring |42. The

collar is slidably mounted on the shaft I9. The weights are pivotally mounted on the collar and have their inner ends disposed in slots in the shaft. 'Ihe spring is so disposed in compression between the outer end of the shaft and the outer end of the collaras to bias the weights to an inner position along the shaft when the motor is notrunning. When the motor is in operation it will rotate the weights and the centrifugal force generated thereby will move them outwardly and hence move the collar along the shaft in accordance with the speed of the motor.

An underspeed switch ||4 is so disposed as to be closed by the movement of the collar |40 -when the motor accelerates to a predetermined speed. This switch stays closed as long as the motor remains above that predetermined speed. An overspeed switch ||3 is so disposed as to be opened when the motor goes above a predetermined speed. The underspeed switch prevents the closing of a self-holding circuit for the motor after it starts until it reaches a predetermined speed. The overspeed switch opens to stop the motor when it exceeds a predetermined safe speed. The overspeed switch is constructed upon the same principle as the switch 50 so that after being opened it cannot be closed without manual resetting, thereby calling the attention of the attendant to the condition of the stairway before it can be restarted.

Referring now to the schematic diagram ofthe motor and control system shown inFig. 5, the main switches and relays in the control system are designated as follows:

A=Current overload relay. B=Phase protective relay.

C=Time control relay for controlling accel- The contact members of the relays are Adesignated by the same reference letters as the relayswith added numerals to indicate the specific contact members.

The driving motor I8 comprises a squirrelucagerotor 95, (Fig. 5) and field windings 88, 91 and 98. A plurality of resistors 98, |88 and ll are provided for controlling the speed of the motor. The supply conductors LI, L2 and L3 to the motor field windings may be connected to a suitable source of supply by a switch |82.

The control system, as shown below the motor diagram, is preferably designed for direct current operation, and its supply conductors L4 and L5 are shown as adapted to be connected toI the supply conductors Ll, L2 and L3 by a suitable rectifier |03, preferably of the copper oxide type. Inasmuch as rectiers of this type are old and well known, no further detailed description thereof will be given.

The energization of the motor I8 is controlled by the line switch J and its direction of operation is controlled by an up direction relay H and a down direction relay K. The line switch J and the direction relays H and K are in turn controlled by an up direction switch F and ament to energize the up direction switch F. The

stairway may be started for down: operation by pressing a down pushbutton |08 at the upper terminal, or a clown pushbutton |09 at the lower terminal, or a down pushbutton I8 in the motor compartment to energize the down direction switch F.

The speed of the motor is controlled by the accelerating relay E for connecting and disconnecting the resistors 89, |88 and |8| in-the circuit for the field windings of the motor. The time control relay C delays the operation of the accelerating relay E for a predetermined period after the motor is first energized, so. that the resistors 99, |88 and |8| will not be disconnected from the motor until the motor starts.

Although any timing relay may be used I have indicatedone provided` with the usual energizing coil and a neutralizing coil CN. The neutraliz ing coil is connected across the supplyconductors L4 and L5 for continuous energization and thereby delays the operation of the relay when its! main energizing coil is deenergized. The time control relay C is controlled, in turn, by the line switch J, so that the accelerating relay is energized a predetermined time after the line switch is energized and is deenergized immediately when the line switch is deenergized.

The eleCtlOmagIlet coil 'Il on the motor brake 752i; g

'I0 is controlled by the line switch J and the direction relays H or K, in such manner that the motor brake coil is energized to release the motor brake as soon as the line switch and one of the direction relays are energized to start the stairway and to apply the motor brake whenever the line switch and the associated direction relay are deenergized to stop the stairway.

The stairway may be stopped by pressing either a stop button I I 6 at the upper landing, a stop button I I'I at the lower landing, an inching button I I8 in the motor compartment, or an inching button.- I I9 located near the sprocket wheels at the lower landing. When one of these buttons is pressed, it deenergizes the line switch J and the associated direction relay to effect the stopping of the stairway.

The coil M of the emergency brake is so controlled that it is energized to immediately release the emergency brake upon the starting of the stairway but is not deenergized until after the expiration of a predetermined time after the stairway stops. The coil is controlled directly by the emergency brake relay P which is controlled by the brake timing relay D which is controlled by either the up direction switch F or the down direction switch G. The brake timing relay is provided with a neutralizing coil DN connected across the supply conductors L4 and L5 for constant energization so that the relay D will not operate after being deenergized until the expiration of a predetermined period of time. The running relay O is also energized by the up direction switch F or the down direction switch G and operates to provide a holding circuit for the timing relay D while the stairway is in operation.

As stated above, when the stairway makes a normal stop, the emergency brake is applied after the expiration of a predetermined period of time after the stairway motor has been disconnected from its supply conductors. The circuit for the coil of the emergency brake is also controlled by normally closed contact members l2I on the switch 86 controlled by the safety Shoe 81. If the chain breaks, the shoe will drop downwardly by reason of gravity, thus opening the contact members IZI and thus immediately applying the emergency brake to stop the stairway upon breakage of the chain.

In order to protect the motor and the control system in their operation, the current overload relay A has its coils included in the supply conductors LI and L3, the phase protective relay B has its coils connected across the alternating current supply conductors and a plurality of fuses I22, |23 and |24 are connected in circuit with the supply conductors leading to the rectier |03.

If the current on the motor I8 becomes excessive, the overload relay A will open its contact members AI in the circuit for the line switch J, and thereby deenergize that switch to stop the motor and apply the motor brake. Upon phase reversal or failure, the phase protective relay B will become eiective to open the contact members BI in the circuit of the line switch J to stop the motor and the stairway. Under other conditions, if the fuses I22, B23 and |24 are blown by an excessive load, the rectier |03 and consequently the control circuit will be deenergized, thereby deenergizing the line switch J and effecting the stopping of the motor and the stairway.

A. control switch |29 is disposed in the circuit of the line switch J. This switch may be located at any desirable point, for instance, in the motor compartment, where it may be opened to prevent operation of the stairway while it is being cleaned, inspected or repaired.

`A plurality of resistors RI, R2, R3, R4 and R5 are included, respectively, in series with the neu- In order to provide for dissipating energy when the circuits are interrupted, I have provided a resistor R6 in parallel with the motor brake coil II2, a resistor R'I in parallel with the emergency brake coil M, and a resistor R8 in parallel with the coil of the time control relay C.

Operation of stairway 'The stairway may be operated as follows: It

will be assumed that an attendant presses the up button |65 at the upper landing to start the stairway for upfoperation. It will be necessary for the attendant to keep this button in closed position until the stairway starts and accelerates to such a speed. The pressing of the button |05 energizes the up direction switch F by a circuit extending from supply conductor L4 through the contact members of button |65, coil F and the contact members GI to the supply conductor L5.

The energization of the up direction switch F opens its contact members FI and closes its contact members F2 and F3. The opening of the contact members FI electrically interlocks the down direction switch G to prevent its energization while the up direction switch F is energized. The closing of the contact members F2 prepares but does not complete the circuits for the line vswitch J and the up direction relay H. The closing of the contact members F3 energizes the running relay O and the brake timing relay D by a circuit extending from the supply conductor L4 through the contact members E4 thence in parallel through the coils O and D and thence through the contact members F3,

closes its contact members DI and thereby ener-` gizes the emergency brake relay P by a circuit extending from the supply conductor L4 through the contact members E4, conductor I3I the contact members DI and the coil of relay Pto the supply conductor L5.

The energization of the emergency brake relay P closes its contact members PI thereby energizing the emergency brake coil M by a circuit extending from the supply conductor L4 through the Contact members PI, M2, the coil M and the contact members I2I to the supply conductor L5. The energization of the emergency brake M of the electromagnet 8l pulls upwardly on the rod 83 and thereby lifts the brake arm 'I6 to= release the brake band 'I4 from the drum 'I5 and thus prepare the stairway for operation.

The energization of the emergency brakecoil circuit and thereby inserts the resistor R4 in series with the coil M, thus reducing the current consumption of the coil and preventing it from overheating while it is energized during continuousY operation of the stairway.

' The energization of the emergency brake also closes its' contact members MI thereby energizing the up Vdirection relay H and the line switch J by a'circuit extending from the supply conductor L4 through the contact members F2, the coils of relay Hand line switch J, the contact members MI, BI, II3, AI and E3, switch |29, contact members of push buttons IIG, I I1, IIS and.y II9 and the contact members I2| to the supply conductor L5.

'The energization of the line switch J closes. its contact members J I J2 and J3 and opens its contact members J4. The closing of the contactI 'members -J I and J2 connects the driving motor I8 to the supply conductors LI, L2 and L3 in preparation for starting the motor. The closing of the contact members J 3 prepares for energizationv the circuit of the machine brake coil 1I. The opening of the contact members J4 opens the circuit of the time control relay C, but'that relay does not yet operate because of the eiect of its neutralizing coil CN.

The energization of the up direction relay H closes its contact members HI, H2, H3 and H4. The closing of the contact members HI and H2 completes the circuit for energizing the motor I8 to operate the stairway in the up direction. One branch ofthe circuit extends from the switch |02 through the supply conductor LI, the contact members J I, coil A, coil 93, and resistor 99 tothe junction point |32; the second branch of thecircuit extends from the switch |02, conductor L2, contact members HI, coil 91 and re'- si-stor |00 to the junction point |32.; and the third branch extends from the switch `I|l2 through the conductor L3, contact members J2 and-H2;-=coil A,'coil`98 and resistor I0! to the junction point |32.l At the same time the closing of the contact members H3 completes the circuit for energizing the machine brake coil il t'ov release the bra-ke 10 by a circuit extending from the supply conductor L4 through the contactfmembers H3 and E3, coil 1| and contact members -J3' to the supply conductor L5. The energization of the motor I8 and the brake coil il'-starts-the' motor and releases the machine brake so that the stairway now starts Vin operation for ythe updirection. The closing of the contact members H4 closes one gap in a selfh'olding `circuit for the relay H and the switch J. 'Referring again to the deenergization of the time control relay -C, by the opening of the contact members J4, it will be assumed that several seconds have passed and that this relay now responds to its deenergization and closes its 'contact members CI, thereby energizing the accelerating 'relay E by a circuit extending from the supplyrconductor L4 through the contact members H3, conductor |33, coil E and the contact members CI to the supply conductor L5.

Enrgiz'ation of the relay E closes its contact members El, E2 and opens its contact members E3 and E4. The closing of the contact members -EI and E2 short circuits the resistors 99, |00 fand VIIlI connected in the 'leld circuit of the motor I8 and thereby causes the motor to accelerate and operate the stairway at full speed.

The opening of the contact members E3 inserts'the resistor R2 in the circuit -of the motor bra'kel coil 1=I-, thereby cutting down the current supply to that coil and preventing its overheating vwhile the brake is being held in its released position and also reducing the load upon the rectifier |03. The opening of they contact members E4 inserts the resistor R5 in the circuit for the relays O, vD and P, thereby cutting ldown the current through these coils to prevent their over-heating in operation and also to reduce the load -on the rectier |03.

`As the driving moto-r I8 accelerates to full speed operation, the safety governor 90 operates to Vclose its underspeed contact members -I I4, thereby completing a self-holding circuit for the up direction relay H and the line switch J. This self-holding circuit extends from the supply conductor L4 through the contact members II4 p of the `governor 90, resistor R3 and the contact members H4 to the coils H and J.

tion of the stairway, the attendant may release the up direction button |05, thereby deenergizing n the up direction switch F to close its contact members Fi and open its contact members F2 and F3. 'I'he closing of the contact members FI has no effect, but the opening of the contact members F2 compels the current to the relayH 'and the line switch J to follow through the selfholding circuit completed by the closing cf the contact members II4 of the safety governor 30, thereby inserting the resistor R3 in this circuit. The resistor R3 cuts down the current to the coils H and J, thereby preventing their overheating during continued energization and also reduces the load upon the rectier |03.

Byreason of the operation just described, it will be seen that the car attendant in starting the stairway into operation presses one of the starting push buttons and holds it inA its depressed position until the stairway accelerates to such predetermined speed that the safety governor 90 completes the self-holding circuit for the direction relay and line switch and that the attendant may then release the pushbutton and the stairwa'y'will continue in operation until it is stopped hby operation of one 'of the stopping buttons-or by `operation'of o-ne of the safety devices.

"It will now be assumedl that the attendant, desiring to stop-the operation of the stairway, presses the 'down stop button 'I I6 at the upper landing. YThis operation opens the vcircuit for the -updirection relay H and the line switch J, thevrunning relay O and the emergency'brake timing relay D.

Thev deenergization of the up direction relay H opensits contact members HI, H2, H3 and H4. The opening of the contact members HI and H2 deenergizes the driving motor I8 and stops it. The opening of the contact members H3 ldeenergizes the machine brake coil 1I, thereby applying thebrakel to stop the operation `of the driving motor and the stairway. The open,- ing of the Vcontact members H4 Vopens the selfholding circuit of the motor H, but this has no effect as the relay H has already been deenergized bytheopening of the contact members of the stop button II6`. y

'I'he deenergization of the line switch- J also opens its contact members J I ,v J2 and J3 in the circuits -for vthe motor I8 Vand the machine brake coil 1I.

The deenergization of the line switch J also closes its contactmembers J 4,thereby energizing the time Acontrol relay C to open its contact members CI, Vtherebydeenergizing accelerating relay to :close its contact members EI and E2 to reinsert the resistors 99, |09 and IDI in the motor circuit, and to close its contact members E3 to short circuit the resistor R2 in the circuit for the motor brake coil 'll in preparing the motor circuit and the control circuit for restarting.

The deenergization of the relay O opens its contact members OI, thereby deenergizing the brake timing relay D. However, because of the neutralizing coil DN on the brake timing relay D, this relay delays opening its contact members .DI for a predetermined period (in this case approximately 5 or 6 seconds). The delayed deenergization of the relay P causes its contact members to now open and deenergize the emergency brake coil M, thereby applying they emergency brake to the driving sprocket wheels of the stairway approximately five seconds after the setting of the machine brake.

As stated above, the setting of the emergency brake occurs everytime the stairway stops, but does not takev place until after the expiration of a predetermined period of time such as five or six seconds after the machine brake has set to stop the stairway. Inasmuch as either brake is sufficiently strong to stop the stairway, it will be understood that if both brakes were set simultaneously the braking action on the stairway would be too severe. Therefore, the provision of the timed delay emergency brake provides not only a flexible and effective braking operation for the stairway, but also provides an absolutely safe braking system.

By following the circuit for the up direction relay H and the line switch J, which control the operation of the motor and the motor brake, as well as the delay operation of the emergency brake, it will be observed that this circuit includes lthe contact members Ml of the emergency brake, the contact members BI of the phase protecting relayB, the contact members H3 of the safety governor 90, the contactvmembers Al of the overload relay, the contact members 63 of the stop chain switches 60 and the contact members I2| of the .driving chain safety switch 86. Inasmuch as these contact members are normally closed during the operation of the stairway, it will be seen that if the emergency brake is deenergized, or the phase protective relay is operated, or the safety governor 90 operates at high speed, or the overload relay A is operated, or either of the stop chain switches E0 is operated by stretching, breakingor catching of the step chains, or the Contact members I2l are opened by the breaking of the drive chain, the line switch J will be immediately deenergized to stop the stairway.

It will be assumed now that the stairway is again placed in operation for the up direction as previously described and that while it is so operating at full speed, the driving chain breaks. The breaking of the driving chain will permit the weighted shoe 81 to move downwardly and thereby operate the rod 84 and the lever 85 vto open the contact members |21` of the switch 86. The opening of the contactmembers l2! 'immediately opens the circuit of the emergency brake coil M to instantly apply the emergency brake to the driving sprocket wheels of the moving stairway, thereby making an emergency stop of the stairway. At the same time the opening of the contact members I2I deenergizes the up direction relay H and the line switch J to immediately stop the motor l'and apply the machine brake on the motor shaft, as previously described. Hence it is seen that the provision of the emergency brake and its control system provides an additional safeguard for the operation of the stairway.

It will also be apparent that the provision of the machine brake and the delayed operation of the emergency brake, as well as the low speed contact members on the safety governor 90 provides a system whereby the stairway maybe inched along by the attendants when it is desired to make repairs or slowly move the steps to some predetermined point. For instance, if one of the starting buttons is held in closed position to start the stairway and one of the inching buttons H8 or H9 or one of the stop buttons H6 or l Il is pressed before the stairway comes up to the degree of speed whereby the governor contact members H4 are closed, the stairway motor will be started at slow speed and stopped after it goes only a very short distance, and that by immediately releasing the inching button or the stop button before the emergency brake is applied, the stairway may be again started and stopped at slow speed. It will be apparent that the inching operation may be kept up by pressing one of the inching buttons or one of the stop buttons before the motor accelerates to a position whereby the low speed governor contact closes, and by again releasing the inching button or the stop button before the expiration of the time when the emergency brake sets, until the stairway steps are moved to the point desired or until the slow speed inspection is completed. y By reason of the foregoing description, it will be seen that I have provided for the operation of a moving stairway under all conditions in a safe and simple manner.Y l p,

Although I have illustratedl and describedA only one specific embodiment of my invention, itis to be understood that many modifications thereof `and changes therein may be made withoutideparting from the spirit and scope thereof.

I claim as my invention:l y l 1. A machine, a drivemotor, a control system for effecting energization and deenergization of the motor,v a shaft for the driving motor, means connecting the shaft to the machine whereby movement of the one will be transmitted to the other, a machine brakefor the shaft, meansv responsive to deenergization of the motorvfor applying the machine brake to the shaft, van emergency brake for the machine, meansresponsive to operation of the control system to deenergize the motor for applying the emergency brake to the machine, and means responsive to operation of the control system for delaying the application of the emergency brake toy the machine for a predetermined period of time after the application of the motor brake.

, 2M. In. a -moving stairway having an endless series of steps, a gear chain for operating the steps, a driving sprocket wheel for operating the gear chain, a driving motor, a control system for energizing andV deenergizing the motor, a shaft for the driving motor, a machine brake for the shaft, means connecting the driving shaft to the driving sprocket wheel whereby operation of the one causes operation of the other, an emergency brake for controlling the driving sprocket, means responsiveto operation of the control system to deenergize the motor for applying the machine brake to the shaft .to stop the motor and the stairway for applying the emergency brake to stop the driving sprocket wheel and for delaying the application of the emergency brake for a predetermined period of time after deenergization of the driving motor.

3. In a moving stairway having an endless series of steps, a pair of gear chains for operating the steps, a pair of driving sprocket wheels for operating the gear chains, a driving motor, a control system for eiecting energization and deenergization of the driving motor, means connecting the driving motor and the driving sprocket wheels whereby rotation of the one effects rotation of the other, a machine brake for stopping the driving motor, an emergency brake for the driving sprocket wheels, means responsive to operation of the control system to deenergize the motor for applying the machine brake to stop the motor and the stairway, for applying the emergency brake to the driving sprockets and for delaying the application of the emergency brake for a predetermined period after the deenergization of the driving motor.

4. In a moving stairway having an endless series of steps, a pair of gear chains for operating the steps, a pair of sprocket Wheels for operating the gear chains, a driving motor, means connecting the driving motor to the driving sprocket wheels whereby rotation of the one effects rotation of the other, a machine brake for controlling the motor and the stairway, an emergency brake for controlling the sprocket wheels and the stairway, a plurality of circuits for the motor, the machine brake and the emergency brake, control relays for controlling the circuits to energize and deenergizethe motor, a relay responsive to operation of the control relays for effecting application of the machine brake to stop the motor and the stairway, a relay for controlling the emergency brake, and a time delay relay responsive to operation of the control system in deenergizing the motor for controlling the emergency brake relay to effect application of the emergency brake to the driving sprocket Wheels only upon the expiration of apredetermined period of time after the operation of the control system to deenergize the driving motor.

5. In a moving stairway having an endless series of steps, a gear chain for operating the steps, a driving sprocket wheel for operating the gear chain, a driving motor, means connecting the driving motor and the driving sprocket wheel whereby rotation of the one eiects rotation of the other, a machine brake for the driving motor, an emergency brake for the driving sprocket wheel, a control system for the motor, and means responsive to operation of the control system to start the motor for releasing both brakes and means responsive to the operation of the emergency brake for preventing operation of the control system tq energize the driving motor until the emergency brake is released.

6. In a moving stairway having an endless series of steps, a motor for driving the steps, a brake for controlling the operation of the steps, a control system for the motor, a control device, means responsive to operation of the control device for effecting the release of the brake and for preparing the control system to effect the starting of the motor, and means responsive to the release of the brake for causing the prepared control system to eiect the starting of the motor.

EDGAR M. BOUTON. 

